a,b,c=map(int,input().split())
perimeter=a+b+c
s=(a+b+c)/2
area=(s*(s-a)*(s-b)*(s-c))**0.5
if a+b>c and a+c>b and b+c>a:
    print("area = %.2f; perimeter = %.2f"%(area,perimeter))
else:
    print("These sides do not correspond to a valid triangle")